As America’s top diplomat arrives in Beijing, one issue looms larger than any other: North Korea. Despite underlying strategic tensions,

Photo: AP/Mark Schiefelbein

As America’s top diplomat arrives in Beijing, one issue looms larger than any other: North Korea.

Despite underlying strategic tensions, officials insist the relationship between Donald Trump and Xi Jinping remains rosy. This is partly because Beijing has been more willing to turn the screws on North Korea in the past six months that it has over the previous six years.

But the Middle Kingdom is reluctant to totally isolate Kim Jong-un. August data shows China imported 1.6 million tonnes of North Korean coal—the largest monthly figure since February. Chinese corn and rice exports also rose sharply.

The high stakes are heaping pressure on the US-China relationship. Beijing is concerned that Washington might decide to enact unilateral sanctions on Chinese banks doing business with North Korea; China Merchants Bank and state-owned Agricultural Bank of China have been named by the chair of the House Foreign Affairs Committee. Such measures would undoubtedly trigger retaliatory moves, sparking fears of a tit-for-tat trade war between the world’s two largest economies.

Mr Tillerson has his work cut out for him. He must seek assurances that China will bring its full weight to bear on Pyongyang, while also preserving cordial ties lest the world’s most important relationship turns hostile.